The Biomedical Simulations Resource (BMSR) at the University of Souther California was established in September 1985 through Grant No. RR-01861 from the National Center for Research Resources of the NIH. The BMSR is dedicated to the advancement of the state of the art in biomedical modeling and simulation through Technological Research and Development (Core) and Collaborative Research projects. It also seeks the dissemination of this knowledge and related software through Service, Training and Dissemination activities aimed at the biomedical community at large. The latter activities include development and distribution of modeling/simulation software, short-courses, workshops and publication of research volumes-in addition to publications in the open literature. The emphasis of the Core Research projects is on development of advanced modeling and simulation methodologies and their application to physiological systems for the advancement of knowledge and improvement of clinical practice. The challenging cases of non-linear, non-stationary, sparse-data, feedback and physiological control systems, as well as the modeling/simulation of complex biomedical systems, constitute the focal points of this effort. The methodologies developed by the Core projects are at the cutting edge of research in this area. Their effective study is made possible by the computing facilities and human resources that are brought together in the BMSR. Pivotal applications of these methodologies cover a variety of physiological domains, including pharmacokinetics, cardiorespiratory, neural and sensory systems. Additional applications, serving as testing grounds and dissemination means for the developed methodologies, are made in our Collaborative projects. Fully developed and tested methodologies are implemented in user-friendly software packages and made available to the biomedical community at large. The Service, Training and Dissemination activities of the BMSR seek to promote the exchange of knowledge and technology in the area of biomedical modeling and simulation. They also aim at creating an interactive community of investigators, which can provide the multi-disciplinary scientific/technological impetus needed to transcend the barriers imposed by the complexity of the subject. The ultimate objective of the BMSR is to facilitate transfer of simulation science and technology to the clinical environment for the improvement of our health care system.